Joining the cornucopia of vaporware Skype WiFi phones (and the occasional phone using the SIP industry standard which no-one seems to actually use outside of the enterprise) is
a Google Talk phone; that's a WiFi-enabled mobile-phone-sized unit that connects to Google's voice-over-IP network. The advantages: the unit will have "Gmail capabilities" built in (which means that all they'd have to do is widen the keybad and they could call it a Googleberry). The disadvantage, of course, is that all your friends are on Skype, which refuses to connect with other networks (other than the analogue phone system).